One of the greatest technical challenges during hand-assisted laparoscopic surgery such as sigmoid colectomy or ileo-colic resection is retracting loops of small bowel which drop repeatedly into the surgical field and obscure visualization. The lack of structural integrity of the bowels and organs allows them to impinge upon the workspace and interfere with the work of the surgeon. The usual method to prevent this interference is positioning the operating table into steep Trendelenberg position so as to allow gravity to assist in favorably shifting the viscera in a superior direction, but this can labor breathing and adversely affect circulation not to mention risk patient injury and positional hypotension.
Conventional retractors are sometimes used to retract bowels and organs from the workspace, but the slipperiness of the tissue can be a nuisance and can contribute to loss of retraction at crucial times. So, devices to prevent prolapse of small bowel loops into the operative field during laparoscopic or open abdomino-pelvic surgery have been developed. For example, small bowel is known to be packed proximally in the abdomen using laparotomy pads or towels. Laparotomy pads or towels inadvertently left inside the abdomen, however, pose the risk of surgical complication with serious consequences. Other methods of retracting the small bowel into the upper abdomen utilize a plastic bag, into which the small bowel is placed and usually secured by means of a pull-cord around the opening of the bag. This approach does not provide retraction of the small bowel out of the pelvis and additionally risks strangulation of the bowel itself from constriction of the mesenteric blood supply.
Some devices have tried to solve these issues by providing a frame with a membrane attached thereto. For example, US 2011/0172495 to Armstrong describes a biocompatible deformable retractor that comprises a deformable resilient frame and a deformable membrane attached to the frame. The retractor can be deployed inside the body cavity by deforming the retractor, inserting the deformed retractor into the body cavity through a surgical opening, and releasing the retractor in the body cavity to retract the organ in the cavity to form the working space. In Armstrong, the membrane can be constructed from a biocompatible sheet, fabric, net, or a combination thereof. Armstrong also discusses that, in some embodiments, it may be desirable to have perforation on the membrane for the purpose of passing surgical instruments such as a laparoscope through the membrane or that the membrane can alternatively be constructed from material that can be punctured by medical instruments. However, new retracting devices are desired.